Industrial truck



Aug. 26, 1952 l G. TURNER 2,608,315

INDUSTRIAL. TRUCK Filed sept. 13. v1949 4, sheets-sheet 1 IN V EN TOR.

GEORGE L. TURNER ATTY.

Aug. 26, 1952 cs. L. TURNER INDUSTRIAL TRUCK 4 Sheets-Sheet 2 FiledSept. 13, 1949 INVENToR. GEORGE L. TURNER BY IfnT'rY.

llg- 26 1952' E v G. L. TURNER 2,608,315

l l INDUSTRIAL TRUCK Filed sept. 15, 1949 4 sheets-sheet 5 FIG. 3

37 39 v E V f I l l :l l /l 56 3B ,/f [l 4 l \l I l l l I I I l l i 35/40 INVENTOR.

GEORGE L. TURNER BY M l www) ATTY.

Aug 26, 1952 G. L. TURNR v 2,608,315

INDUSTRIAL TRUCK Filed sept. 13, 19494 4 Sheds-Sheet 4 INVENTOR.

GEORGE L. TURNER AT-rv Patented Aug'. 26, 1952" INDUSTRIAL TRUCK GeorgeL. Turner, Buchanan, Mich., assignor to Clark Equipment Company,

Buchanan, Mich.,

a. corporation of Michigan Application september 13, 1949, serial No,115,397

supporting carriage is actuated vertically by` means of a hydraulicpiston and cylinder assembly. In the construction referred to a pair offrame members extend transversely of the truck and are secured totheload supporting carriage in a manner to permit vertical movementtherewith. A plurality of forks are either hooked over the uppertransverse frame member, or are bolted or -otherwise suitably secured tothe forward face oi the transverse frame members to enable use of thetruckfor picking up and depositing loads.

This type of load supporting means is unsatisfactory forA use withaheavy duty industrial truck for which the forks must of necessitysupport a load of `substantial weight. The momentum of a heavy dutytruck, when engaging a heavy load supportedon a pallet may, ifmanipulated by an inexperienced driver, cause an impact betweentheljunction of the vertical and horizontal legs of thel forks. l. r flAn object of the present invention is to provide box-like transverseframe means providing for the support of a plurality of forks.LPreferably a pair of box-like frame means are arranged in verticallyspaced relation on the load supportingcarriage of the truck and eachboxlike frame means includes horizontally spaced vapart fro-nt and rearwalls between which the vertical leg portion of the forks are adapted toeX- tend. mThe upper ends of the forks are preferably provided withdetachable block members for engaging the upper edges of the fro-nt andrear walls of the upper box-like frame so that the forks are adapted tobe raised upon raising of the load supporting carriage. The frontsurfaces of the front walls of the box-like frames are adapted `toengage the rear surface of a load and are thus effective in preventingthe lower rear edgeof the load, orla pallet, if the load is supportedthereby, from contacting'the junction between the vertical andhorizontallegs of the'forks. This construction thus prevents an impact fromoccurring between the loadand fork junctions thus eliminating damagetothe pallet or load.

j'j ,"lhemaforementioned vertically extending mast of known trucksis-tiltable either forwardly or 4 Claims. (Cl. 214-113) 2 rearwardly, bymeans of one or more-hydraulic piston and cylinder assemblies, which aresecured adjacent one of their ends to the frame of the truck, andadjacent their other ends to the mast. If the mast is tilted Vrearwardlywith a load on theforks, the center of gravity `of the load and thecenter of gravity `of the mast is shifted to a position closerto thefront wheels, thusproviding greater stability `for the truck. However,if the mastand load are tilted forwardly, thecenter of gravity of `themast-and-center of gravity ofthe load are shifted to a positionforwardly ofthe front wheels, thus causing the truck tobe unstable,which in extreme cases may result in overturning of the truck.

A further object of the present invention is to provide an industrialtruck with a mast fixed adjacent the forward end of the truck, and withwhich a tilting mechanism is arranged for vertical movement relativethereto. The tilting mechanism provides for thesupport of suitabletransverse frame means which may bev either of the known or improvedforms above referred to, and which in turn provide for the thereon ofsuitable lift forks or other load engaging means, and is adapted to betilted either forwardly or rearwardly as desired by the operator inmanipulating the truck. By providing a tilting mechanism as presentlyproposed, the center of gravity of the mast remains stationary, for itis fixed to the truck, and the center of gr-avlty of the load carried onthe fork supporting frames is shifted only a short distance toward oraway from the Iront wheels of the truck. depending on whether the loadis being or rearwardly.

rlhe advantage of the tilting mechanism Akof the present invention overthe conventional tilting mast, is that even when the tilting mechanism1s moved upward to the top of the mast, the center of gravity of a loadcarried thereon is shifted only a few inches when the tilting mechamsm1s actuated either forwardly or rearwardly, whereas if a load is movedto the top of a conventional mast, and that mast is tilted forwardly,the center of gravity of the load is shifted considerably forward of thetruck, which may produce a movement suiicient to cause the truck tooverturn.

Now in order to acquaint those skilled in the art with the manner ofconstructing and using the devices embodying the principles of thepresent invention, certain preferred embodiments of the invention willbe described. L i

mounting tilted forwardly of the support of a mast, and should 'of fluidunder Figure 4 is a sectional view taken substantially *Y along the line4-4 in Figure 2 looking in the direction indicated by the arrows,

Referring now to Figure 1, there is shown'an n industrial truckindicated generally by the reference numeral I having a main frame (notshown) to which a transversely extending drive axle assembly is mountedadjacent the forward end thereof. Mounted adjacent each end of the driveaxle assembly are a pair of drive wheels II. A pair of dirigible typewheels (not shown) are disposed closely adjacent to each other and arelocated adjacent the rear portion of the frame centrally of the sidesthereof. The pair of rear steering wheels are adapted to be rotated forsteering the truck by means of a steering linkage mechanism, which isactuated by means of the steering column I5 and steering wheel I1, whichare disposed adjacent the forward end of the truck. rIhe truck isfurther provided with suitable prime mover means, clutch and brake meansanda plurality of control levers, indicated generally at I8, Vforeffecting actuation of the various mechanisms of the truck. The truckshown in Figure 1 per se is further described in detail in theVco-pending application of Robert Lapsley l,and George L. Turner, SerialNo. 115,982, filed September 16, 1949. The truck is illustrative only ofone suitable form of industrial truck to which the present invention isapplicable and it will be understood that the truck may vary widelyin'its construction and form. The only 'requirements of the trucknecessary for purinvention is that it be capable preferably embodysuitable pumpmeans driven for example, vby the prime mover means toprovide a, source I pressure to eect raising of a load and actuation ofthe tilting mechanism to be hereinafter described.

A'fmast indicated generally at I2 is mounted in xed position at theforward end of the main frame. The mast I2 in the main is of knownconstruction and comprises a pair of C-shaped channel members I3 whichare disposed in spaced apart parallel relationship and extend verticallyadjacentV each side of the main frame. The C-shaped members I3 are heldin xed spaced poses of the present .relation atA their upper ends bymeans ofv a .C-shaped bracket 2B secured at its opposite ends Ato the.upper portions of each of the C-shaped channelmembers I3. A secondCshaped bracket .member 22 is secured-adjacent its ends to an in`termediateportion of. each of the C-shaped channel members I3. Withineach. of the C-shaped channel members is an inner sliding channel member23. The channel members 23 .are held Ain spaced apart relation by meansof a suitable transverse cross member 25 extending between andsecured tothe upper portions thereof.

The lower endsrof the channel members I3 are suitably secured to aplatform bracket 26, as shown in Figure 4, which is suitably secured. tothe' main frame of ,the truck. The, platform bracket 26 has a recess 21formed therein which is adapted to receive the lower portion of avertically extending cylinder of a hydraulic piston and cylinderactuating assembly indicated generally by the reference numeral 30.Mounted to the free end of the piston rod 3l of the hydraulic piston andcylinder assembly is a pinion housing 32 to which a pair of pulley andbracket assemblies 33 are secured one adjacent each end thereof about anaxis extending transversely of the piston 3 I. The pinion housingadjacent its upper end is suitably secured as by bolts to the crossframe member 25.

Referring now particularly to Figures 2, 3 and 4, I shall describe inconnection therewith the tilting mechanism and transverse box-likeframes which form the subject matter of the present invention. Disposedadjacent ythe inwardly facing side of each of the inner channel members23 is a vertically extending frame member 35. The framek members 35interconnected4 adjacent their forward end by means of av transversehorizontal brace member 36. Rotatably mountedV to the upper and lowerportion of each of the^ vertically extending frame members are a pair ofrollers 31` disposed laterally outwardly therefrom which are adapted tohave rolling engagement with the side walls of the inner C-shapedchannel' meme bers 2,3. A second pair of vrollers 38 are provided foreach of the vertically extending frame-,members, and are disposedlaterally` outwardly therefromv adjacent to and inwardly of the first;rollers 31. The second pair of rollers 38 are; adaptedpto have rollingengagement with the bightportion of each of the C-shaped channelmembers. .Pivotally secured t-o each of the upper forward ends of thevertically extending frame members 35v as at 39 is a downwardlyldepending load` carrying frame member 4B. A pair of hydraulic piston andcylinder assemblies 42 are disposed between the lower endporti-ons offrame members 3,5; and '40, and the outer end. of eachof` the pistons isprovided with :a clevis 42 havingA pivotal connection as at 43 with thevlower endsof the load carrying frame membersy 4D'. The closed ends ofcylinders 44 havepivotal connection asin'dicated at 45 with thebifurcated innerend portions 41:70! each of the frame members 35. Thus.trwill; be seen that .the load carrying frame members 4,0 may be pivoted.about their axes 3.9,by' actuating the hydraulic piston and cylinderassemblies, either inwardly or'outwardly, as may.` be desired.

Intermediate of. the ends of the vertically-extending framemembers areapair-ofhorizcntal inwardly extending ,flanges 4.6-, toiwhich one'end of`a pai-r of chains 41 aresecured. The chains are trained about thepulleys of aforementioned bracket assemblies 33 and are secured adjacenttheir other ends to theV intermediate ceshaped horizontal cross member22, which is secured to the intermediate portions of ythe outervertically extending C-shaped channel members I3 ofthe m-a-stv formaintaining the .same inxed spaced relation. Y l

Thus uponthe admission of fluidV under pressure to the cylinder 30, theaforeolescribed inner channels 23 and frames 35 and14 may be caused tobe raised to elevate av load supported byvframes 40 as will bedescribed, f

The load carryingl framemembers III'Iy provide for, the support of upper.andlower transversely extending box-like frame members' 5U and 5I, asbest shown in Figure 1 Each of the boxflike f framev members is denedbyspaced front and rear walls 53 and 54 connected at their opposite endsvby suitable end walls 55. The several walls may be made as separateparts welded together to form the structure described. Asbest shown, theload carrying frames 40 have upper end lower pad portions 56 and 51 towhich the `box-like frames 50 and 5| may be secured, as by bolts or thelike. A pair of forks E are adapted to be supported by the box-likeframe members 50 and for vertical movement relative thereto. rIhe forksB0 each include a vertically extending leg portion B2 adapted to bedisposed between the inner surface of the front and rear walls 53 and 54and suitable block members 63 are secured as by bolting to oppositesurfaces of the upper ends of the leg portions 62 above the upperboxlike supporting frame 50. By virtue of the construction described,the block members l|3 support the forks in the upper edges of the upperbox-like frame 5U and the leg portions B2 are supp-opted between thefront and rear walls of each of the frames 5|] and 5|. constructionfurther permits of the transverse adjustment of the forks. As previouslyrelated, the forks 60 are of substantial weight so that they normallywill not shift laterally. However, if desired, suitable means may beprovided, as by the insertion of spacer blocks between the front andrear walls of the box-like supporting frames for limiting relativelateral movement of the forks.

If it is desired to`lift the tilting mechanism of my present invention,one of the suitable control levers of the groupat I8 is manipulated tothereby admit fluid under pressure to the hydraulic piston and cylinderassembly 3D. When the piston rod of the hydrualic. piston and cylinderassembly 30 is forced upwardly the inner C-shaped channel members 23 arecarried upwardly therewith. The wheels of the assemblies 33 mounted tothe sides of the pinion housing 32 are moved upwardly therewith and thechains 41 which are secured to the intermediate C-shaped brace member 22and the flanges 46 of the frames 42 move the latter upwardly. As may bereadily understood, when the inner C-shaped channel members 23 havereached their upper limit of movement that the tilting mechanism of thepresent invention will be located adjacent the upper portion thereof.

If it should be desired to lower the mast and tilting mechanism theappropriate lever of the group at |8 is suitably manipulated to bleedfluid under pressure from the cylinder of the piston and cylinderassembly 3D. 'I'he weight of the mast and associated parts is sufficientto force the piston rod 3| downwardly to the desired lowered position.Tilting of the forks 60 may be effected by the selective admission offluid under pressure to the cylinders of the piston and cylinderassemblies 42. Thus if the piston rods of the hydraulic piston andcylinder assemblies 42 are caused to be moved outwardly under thepressure admitted to cylinders 44, the vertically extending framemembers 35 will pivot about axes 39 in a counter-clockwise direction asviewed in Figure 2, to dispose the forks 6D in the dot-dash lineposition of this gure. Upon admission of uid under pressure to cylinders44 to effect movement of the piston rods inwardly, the frame members 40will be pivoted about axes 39 in a clockwise direction as viewed inFigure 2 and dispose the forks in the dotted line position of thisfigure. It will be understood that the tilting mechanism of my inventionworks independently of its vertical position within the inner C-shapedchannel members 23 of the mast. Thus the tilting mechanism may beoperated at its lowermost position or at its upper;

most position in the mast.

The construction above described is of advan-v tage in that the centerof gravity of a load supported on the forks 60 of the truck only variesslightly from its position when the forks are horizontal. Assuming thecenter of gravity indicated at X in Figure 2 of a load identified as Ais higher thanthe axes 39 of the frame members 40 as indicated by line Band the load is tilted rearwardly tothe dot-dash line position shown inthis figure, the center of gravity as exemplified by line C moves towardthe drive wheels'l If the center of gravity of the load is lower thanthepivotal moves slightly away from wheels as indicated' by line E.However, if the center of gravity of the loadL is lower than axes 39,then the center of gravity tends to move toward the drive wheels Theadvantage of this arrangement lies in the fact that even though the liftcarriage dened by frame members 35 and 4U is at the top of the uprightsor mast, the center of gravity is moved.

only a small amount upon tilting of the forks 60.

i The transverse box-like frame members 5D andv 5| which have beenpreviously described are par-.-

ticularly adapted for use in connection with heavy duty industrialtrucks. In this connection, the forks are of substantial presentconstruction of the box-like frame mem-l bers the forks may be alignedin a position below the box-like frame members so as to pass through theopenings formed therein when the box-likef frame members are lowered onthe mast. `It isthen only necessary to fasten the pair of plate members63 to the upper most portions of the forks.

While I have shown and described what I consider to be a preferredembodiment of my invention, it will be understood that variousmodifications and rearrangements may be made therein without departingfrom the spirit and scope of my invention.

I claim:

l. In combination, an industrial truck having a main frame, ra verticalmast iixedly mounted to the forward end of said main frame, a pair ofvertically extending spaced apart frame members mounted for verticalmovement in said mast, means for inter-connecting said frame memberswhereby the latter are vertically movable in unison within said mast, apair of downwardly depending load carrying frame members one pivotallysecured to each of the upper forward ends of said vertically extendingframe members about a common axis extending transversely of said truck,a pair of substantially forwardly horizontally extending hydraulicpiston and cylinder assemblies one disposed laterally inwardly of eachvertically extending frame member with the closed ends of the cylindersof said hydraulic piston and cylinder assemblies having pivotalconnection one to the lower portion of each of said vertically extendingframe members, and with the outer ends of the pistons of said hydraulicpiston and cylinder assemblies having pivotal connection one to thelower portion of each of said downwardly depending load carrying framemembers whereby said hydraulic piston and cylweight. By using thenderlassemblies upon :actuation thereofv 4Serieel:

pivoting of said load carrying Lirama members about .said axis.

2;.Load supporting means ,for ian :industrial truck. or the like,e'comprising ,a box-.like frame havingspaced apart elongated front andrear walls rconnected .at their :opposite lends by end. Walls, :at leastone .load supporting fork .of .substantially shape.having theverticalleg yportion thereof .disposed between the inner surfaces ofsaidront and .rear `walls, and stopmeans secured to theiupperiendxportionzof thevertcal -legzoffsaid fork for Anormallyengaging .the `upper redges zoi said A:front tand .rear 'Walls whereby:said :fork is supportedbysaid .box-ine frame when the latter is 'in anyelevated jposition.

3.iLoad 'supporting :means lior .an industrial truck orithedilre,.comprising :a pair .of vertically spaced and .aligned 'ibex-like. framemembers :each having spaced 1apart A.elongated Afront :and rear-conneoted .at .their opposite 'ends 'by lend Walls, at least v.one.load supporting fork .of substantially L-.shape having .the verticalleg portion.

thereof .disposed .between .the inner surfaces y'of said .frontend :rearWalls Iof both of .said box-.like frame members, v.and's'topmeanssecuredzto the upper end portion 'of vthe verticalleg .of saidiforlfor normally 'engaging 'the `upper edges :of said front and rear `wallsof the upper ,box-likefr-ame member 'wherebyasaid fork is :supported .bysaid box-like `frame vmember `when the ylatter is in .an elevatedposition.

' 4. .In combination, Yan industrial truck having amainfra'me, `avertical mast fixedlymounted'to the forward end of said vmain gframe, a:pair .of vertioailyxextending spaced apart framermembers mountedfor'vertical'movement in said mast substantially :Within .the confinesof. the latter, meansor inter-'connecting said iframe lmembers wherebyLtile :latter are vertically :movable in unisonI within vsaid mast, apair of downwardly depending .-loadcarrying frame Amembers onepivotallye-secured to each ofthe upper iorw-ard'ends of said verticallyextending frame `membersabout a ,common :axis extending transversely :ofsaid truck, ,aj pair of substantially iorwardly'horizon# talle7extending .hydraulic piston 4and :cylinder assembliesfonedisposedlaterally:inwardly .oneach vertically y.extending .lf-ramemember with ythe closed ends of the -cylinders of .said hydraulic pistonianduroylinder .assemblies having pivotal conneotionone to the 7lower:portion of .each .of said uverticallyextendingv frame members, .andwith Athe outer ends .of `the pistons .of'saidhydrauliol piston zandcylinder assemblies having pivotal connection one .tothe lower :portion.of each .of said downwardly-.depending .load carrying fframe memberswhereby said .hydraulic piston and -cy1 inder assemblies upon .actuationthereof eiect pivoting .of vsaid fload carrying-,frame members aboutsaid axis, and Vtheoylnders sof ysaid hydraulic misten and cylinderassemblies lyingrsubstantially `With-in the .confines of saidmast.

.GEQRGEL REFERENCES v.CITED "The *following references are fof recordintlie file :of zpatentz.

'UNITED s'rA'rEs PATENTS

